[tiff8968]

Okay, I think I got the basic on how to interpret mass spectroscopy data. The molecular ion peak and is the biggest m/z value and is the heaviest ion that is magnified by the mass spectrometer. However the molecular ion can break into fragments (which I don't fully understand). Also on the graph is the base peak. This is the tallest peak and represents the ion that is most abundant. If a compound has isotopes than this can cause finding the relative formula mass more difficult. My question is am I going in the right direction???

[lucas89]

You are, you are indeed. The usual isotopes you have to worry about are Bromine and Chlorine (their abundance and mass differences will show up and be kind of obvious on the spec). But yeah, keep going with it, you're headed in the right direction.

A helpful hint when it comes to mass spec: if you take the m/z values of your molecular ion peak, and then subtract from that the m/z value of one of the fragments, that value will give you the mass of what has been taken away from that molecule (m/z=15 and 29 come up quite often. If you notice these, think ethane and methane!)